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ISUOG Basic Training
Making a Decision – Normal or Not?
Titia Cohen-Overbeek, The Netherlands
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At the end of the lecture you will be able to:
• describe how to perform a transverse overview/sweep of
the fetal body from neck to sacrum
• recognise the differences between the normal & most
common abnormal ultrasound appearances that can be
excluded by the transverse overview/sweep
Learning objectives 19 & 20
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Transverse sweep – overview 2
• Transverse Sweep from Neck to Sacrum
• Full assessment of thorax, abdomen and pelvis
• Visualization of the vertebrae
• Anatomical landmarks
Slide, rotate, slide, rotate, slide
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• What probe movements are required to perform a transverse overview/sweep of the fetal body correctly?
• Which parts of the fetal anatomy are best assessed using this overview/sweep?
• What are the key ultrasound features that distinguish between the correct & the incorrect view of a vertebra in cross section
• Which abnormalities should be excluded after performing a transverse overview/sweep correctly?
Key questions
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Transverse sweep – overview 2
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Transverse sweep- overview 2
Slide from the head down to the sacrum Ideal position for spine however no fluid between spine and uterine wall
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Transverse sweep- overview 2
Ideal position for spine, but sparse fluid between spine and uterine wall
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Transverse sweep- overview 2
Good position for spine, and fluid between spine and uterine wall
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Transverse sweep- overview 2
Good position to observe spine thorax and abdominal structures
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Transverse sweep- overview 2
Poor visibility of the spine, Good position to observe thorax and abdominal structures
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Spina bifida
The vertebrae become U-shaped instead of their normal triangular form Neural tissue is protruding
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Spina bifida
Confirm any anomaly in more than 1 plane
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Transverse sweep- overview 2 thorax
What can you exclude
Situs anomalies
AVSD
Univentricular heart
Double aortic arch
Right aortic arch
Ectopia cordis
Significant pericardial effusion > 4mm
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Transverse sweep- overview 2 thorax
Confirm in 2 directions
What can you exclude
CPAM
Left sided diafragmatic hernia
Significant pleural effusion >4mm
Skin edema
Spina bifida
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Transverse sweep- overview 2 abdomen
What can you exclude
Situs abnormalities
Ascites
Small/absent stomach
Duodenal atresia
Echogenic bowel*
Gastroschisis / omphalocele
*
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Transverse sweep- overview 2 abdomen
What can you exclude
Bilateral renal agenesis
Cystic renal dysplasia
Lower urinary tract obstruction
Renal pelvis dilatation
2 vessel cord
Sacrococcygeal teratoma
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Making a decision
• When encountering a structure or measurement not compatible
with normal views and biometry:
• Confirm in more than 1 plane
• Confirm measurement > 1 time – consider if in correct plane
• Continue to complete the ultrasound scan and assess whether
the abnormal structure / measurement can be reproduced
• Share with parents your concern the fetus may not be normal
only when the scan is finished
• Request opinion of supervisor
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Making a decision
• Is this ventricle > 10 mm
9.6 -9.9 mm 10.4 mm 10 mm
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Making a decision
• Is the stomach absent? Reassess after 10-20 minutes
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Making a decision
• Is the bowel echogenic?
• Look at BMI,
– low BMI and posterior placenta may cause a too perfect view
– turn down the gain to assess for bowel as white as bone
Not echogenic
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1. In the transverse sweep the position of the spine is vital
for the evaluation of anatomical structures.
2. The spine should present with 3 ossified centers in a
triangle covered by skin
3. When the 3 ossified centers are U-shaped think of spina
bifida and confirm the anomaly in multiple planes
Key points
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4. When encountering an abnormal appearance or
measurement continue to complete the scan, confirm in
multiple planes and with multiple measurements, before
communicating with the parents your final decision to
refer
5. You do not have to make a diagnosis, but you should be
familiar with normal appearances
6. Whenever you are in doubt refer
Key points